DELETE ANY PREVIOUS VERSION! Extract the zip in your Amnesia installation folder. It may ask you to replace, confirm replacement.

English:

Finally the full version of The Maze Of Lost Memories! Extract the zip in your Amnesia installation folder that should be: C:\Program Files (x86)\Steam\steamapps\common\Amnesia The Dark Descent or C:\Program Files\Steam\steamapps\common\Amnesia The Dark Descent.